Vellus Hair Cyst

 Mechanical dermabrasion, retinoids, needle evacuation, simple excision, or laser therapy






Microscopic




• Dermal cyst lined by bland stratified squamous epithelium with granular layer

• Intraluminal laminated keratin debris and numerous vellus hair shafts

• Small hair follicles/pilosebaceous units may be seen attached to cyst wall


Top Differential Diagnoses




• Epidermoid (epidermal inclusion, follicular infundibular) cyst
image Lacks intraluminal vellus hairs

• Milial cyst
image Also lacks intraluminal vellus hairs

• Steatocystoma
image Corrugated, eosinophilic cuticle lines inside of cyst wall

• Trichofolliculoma

image
Clinical Photograph of Eruptive Vellus Hair Cysts
Multiple, slightly brownish, small follicular papules are seen on the chest. This is a classic presentation of eruptive vellus hair cysts. (Courtesy J. Wu, MD.)


image
Vellus Hair Cyst
Low magnification shows a cyst lined by a keratinizing squamous epithelium. The cyst contents include laminated keratin image and numerous transversely sectioned hair shafts image.

image
Vellus Hair Cyst With Pilosebaceous Unit
Some cysts may show a pilosebaceous unit attached to the cyst wall image. Fragments of hair shafts are also present within the cystic space image.

image
Ruptured Vellus Hair Cyst
Ruptured vellus hair cysts are often accompanied by an exuberant foreign body granulomatous response image as is illustrated here, with many hair shafts surrounded by inflammation.


TERMINOLOGY


Abbreviations




• Vellus hair cyst (VHC)


Synonyms




• Eruptive vellus hair cyst (EVHC)


Definitions




• Similar histology to epidermoid (follicular, infundibular type) cyst with addition of intraluminal vellus hairs


ETIOLOGY/PATHOGENESIS


Genetics




• Rare cases reported to be autosomal dominant
image Rarely associated with the following diseases

– Ectodermal dysplasia (anhidrotic and hidrotic)

Only gold members can continue reading. Log In or Register to continue

Related posts:

  1. Squamous Cell Carcinoma In Situ (Bowen Disease)
  2. Porocarcinoma
  3. Multinucleate Cell Angiohistiocytoma
  4. Lymphoepithelioma-Like Carcinoma of Skin

Stay updated, free articles. Join our Telegram channel
Tags:
Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Vellus Hair Cyst

Full access? Get Clinical Tree
Get Clinical Tree app for offline access